/Engine/Plugins/Runtime/XRBase/Source/XRBase/Public/HeadMountedDisplayFunctionLibrary.h
Returns whether or not we are currently using the head mounted display.
(Boolean) status of HMD
[UFUNCTION](Programming/UnrealArchitecture/Reference/Functions)(BlueprintPure, Category="Input|HeadMountedDisplay", Meta=(KeyWords="HMD")) static bool IsHeadMountedDisplayEnabled()